Novel low aspect-ratio Si nano-hemisphere array surface texture application to ultrathin film solar cells

Low aspect-ratio Si nano-hemisphere array surface texturing compatible to thin film based solar cells is studied systematically for performance improvement. The light reflection can be significantly suppressed through varying the nano-hemisphere dimensions due to the spatial effective refractive index modulation. Owing to the excellent light trapping and also the nature of low aspect ratio (critical for conformal deposition of electrodes and achieving low surface defects), a short circuit current density (J_sc) of 37.4 mA/cm² is realized, in distinct comparison with the J_sc of 20.4 mA/cm² measured from the reference flat solar cells.